1. Field of the Invention
The present invention relates to the field of computer networking, specifically to the field of local area networks using active hubs or concentrators.
2. Description of the Related Art
The present invention provides for a protocol independent switch or central device for use in a local area network or the like.
Historically, numerous protocols have evolved and have gained varying degrees of acceptance in the marketplace. Of course, it can be expected in the future that additional protocols will also be developed, for example, to fill new needs and to take advantage of new technologies.
Examples of existing protocols include the well known IEEE 802.3 standard--sometimes referred to as CSMA (carrier sense multiple access) or Ethernet--and the IEEE 802.5 standard, sometimes referred to as token ring. Existing protocols also include the FDDI standard.
Examples of emerging protocols include various proposals for 100 Mbps Ethernet.
Local area networks are known to include any number of central devices which provide for interconnection of data terminal equipment (DTE) in the network. Examples of DTE's include end user computers, file servers, printers, communications devices such as network modems and facsimile products and the central devices themselves. Central devices, as that term is used herein include any number of devices which allow for centralized interconnection of DTEs. Examples include hub concentrators, routers and bridges.
Importantly, from the standpoint of a network manager (an individual or group of individuals assigned the task of implementing and managing a local area network) for various reasons including availability of certain equipment, requirement for particular functionality, etc., it can be expected that DTEs in a local area network may utilize any of a plurality of the various protocols. It is, therefore, important that the central device to which these various DTEs is coupled, is configured to allow for proper communication dependent on the protocol of the particular DTE.
Of course, one simple solution is to provide for multiple ports on the central device--for example, a set of ports to support DTEs transmitting in the CSMA protocol and a separate set of ports to support DTEs transmitting in the token ring protocol. In fact, this has been done in the prior art and is often implemented by allowing for insertion of multiple modular cards where, for example, a first modular card may have a plurality of ports for support of CSMA protocol DTEs and a second modular card may have a plurality of ports for support of token ring protocol DTEs. This is illustrated by FIG. 1 which shows a hub concentrator 101 having a plurality of insertable module cards for supporting various network protocols. This is not an ideal solution at least because if a user switches DTEs, say from using a DTE which utilized the CSMA protocol to using a DTE which utilizes the token ring protocol, the connection on the central device must be physically changed.
One alternative solution that has been proposed is to utilize a front-end switch such as mechanical switch 201 which provides for accepting a plurality of incoming connections from DTEs in the local area network. As illustrated, the switch 201 provides for accepting connections for 100 DTEs. The switch 201 may then be controlled (for example, through use of a separate controller such as illustrated as controller 202) to provide for switching of the incoming connections to appropriate ones of the various ports on the central device 203. While this solution may avoid the need for physically changing connections when a DTE using a new protocol is introduced into the network, there is nonetheless a continuing need for intervention by a network manager.
It should be noted that in addition to the problems with requiring network manager intervention to allow switching of a DTE in a local area network, the prior art utilizes modular insertable cards as has been discussed. However, again as has been discussed, there is the need in the prior art to utilize one type of a modular card for support of one protocol and another type of a modular card for support of another protocol. This leads to issues with availability of necessary resources. For example, a hub concentrator in a local area network may have 3 CSMA protocol modular cards each having 16 ports for a total of 48 CSMA protocol ports and 2 token ring protocol modular cards each having 16 ports for a total of 32 token ring ports. However, the network, for various reasons, may have need to support say 56 CSMA protocol devices and only 24 token ring devices from the particular hub concentrator. Thus, although support is only required for 80 DTEs, the hub concentrator is not capable of supporting the required configuration without modification.